The present invention relates to a portable oven for warming food products. The warming oven is constructed of light-weight, inexpensive materials yet provides an efficient food warmer which may be operated in a convenient manner by persons of limited skill. More particularly, the present invention relates to a portable warming oven having a wire rack frame assembly surrounded by a flexible heat insulation material, and a flame producing device for generating heat within the oven.
In the food delivery field, many devices are known for keeping the "product warm during delivery. Such known devices include insulated containers for surrounding a preheated food product to keep it warm for a short period of time. However, these devices are benign and without a heat source to keep the food warm. Such devices are unacceptable for food products which are not preheated, or food products requiring a long delivery time. In addition, such known devices are constructed so as to prevent heat leakage through the joints, seams, and closure edges. A preheated food product placed in such a device quickly generates a substantial amount of humidity inside the container, thus degrading the quality of the food product contained therein. For example, food products containing pastry crusts such as pizza tend to get soggy and unpalatable because the chamber is tightly sealed and does not breath.
Other known food warming devices include oven-light carriers that have self-contained, fueled heat sources. One such device is disclosed in U.S. Pat. No. 2,057,373 to Dukes. The Dukes portable oven includes an alcohol burner located within a rigid and solid oven structure. Shelves are provided on the interior of the oven to hold a food product which is to be warmed. However, it can be appreciated that the apparatus according to Dukes is large, heavy, bulky, expensive to manufacture, and extremely awkward to carry and maneuver. Thus, the Dukes portable oven is not well adapted to home delivery of heated food products, such as pizza. In addition, there is no apparatus for insuring that the heat generated by the alcohol burner is evenly distributed within the oven. Thus, food within the Dukes portable oven may be unevenly heated, perhaps causing scorching of the food product itself.
Another known food heating apparatus is disclosed in U.S. Pat. No. 3,590,802 to Fried. The food warmer of Fried includes a rigid, solid oven structure having a front-opening door and wire racks horizontally disposed therein. However, the food warmer of Fried is connected to the heating system of an automobile to provide heat to the interior of the food warmer. Obviously, such a structure is far from portable and requires a great deal of time and expense to couple to an automobile heating system. It can be appreciated that malfunctions in the automobile heating system will cause a malfunction in the food warming oven, and vice-versa. In addition, the rigid structure according to Fried is extremely heavy, bulky, and cannot be carried or maneuvered once installed in the automobile. The wire racks of Fried are hollow and adapted to receive the heated fluid from the automobile heating system. This evidently provides a uniform heat distribution, but does not permit the vertical adjustment of the wire rack shelves themselves.
Another portable oven is disclosed in U.S. Pat. No. 3,724,440 to Clark et al in which a wire framework is coupled to a pair of rigid side panels. Heat is provided by gas or electric means, which greatly reduces the portability of the oven itself. A disposable oven covering made of aluminum may be wrapped around the wire framework to prevent ambient air currents from affecting the cooking process. However, it is evident that the Clark oven is only portable in the non-heating state. The oven must be connected to a gas or electric source before heating can be accomplished. In addition, the apparatus according to Clark et al is also heavy, expensive, and impossible to carry or maneuver once coupled to a heat source. Furthermore, the apparatus according to Clark et al contains no means to insure the even distribution of heat within the oven itself. Thus, the food product heated within the Clark oven may be heated unevenly.
Other food warming devices are described in the following U.S. patents: U.S. Pat. No. 3,288,129 to Fox; U.S. Pat. No. 4,424,798 to Volk; U.S. Pat. No. 1,545,393 to Bryant; U.S. Pat. No. 2,575,299 to Scheel; U.S. Pat. No. 2,371,410 to Rickenbacher; U.S. Pat. No. 3,074,394 to Witt; U.S. Pat. No. 3,874,361 to Parrinello; U.S. Pat. No. 2,742,850 to LaFond; and U.S. Pat. No. 4,384,513 to Pierick. Each of these food warming devices contains disadvantages which make them inappropriate to a light-weight food warming apparatus which may conveniently yet reliably heat a food product in a uniform fashion.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the difficulties and disadvantages of known food warming devices, described above. The present invention provides a light-weight food warming oven by the inclusion of a wire rack frame which is light-weight yet sturdy and capable of supporting a wide variety of food products within the oven. Surrounding the wire rack frame is a breathable insulation cover which may include a breathable fabric outer shell, a foam insulation material bonded to the inside of the outer shell, and a breathable fabric bonded inside of the foam insulation. The insulation cover preferably has at least one vent therein to further assist the escape of moisture from the oven to prevent humidity buildup within the oven. The vent opening in the insulation cover may also be used to provide a handle by which the oven may be carried. The insulation cover also may include a zippered or otherwise fastened front door to allow easy access to the inside of the oven.
Inside the oven is disposed a source of heat, preferably a flame producing fuel cell capable of providing long-term heat to the oven interior. Above the heat source is disposed a heat distribution plate for insuring uniform heat distribution within the oven. The heat source may be disposed upon a second plate which both supports the heat source and conducts heat away from the heat source to insure reliable operation thereof. Preferably, a retention device is coupled between the bottom plate and the heat source to insure that the heat source remains stably mounted on the bottom plate.
The oven apparatus may also include a plastic base member within which the oven sits. The plastic base member insures structural stability, provides protection to the oven, and retains any spilled food or fuel within the oven itself. In one embodiment, the plastic base member comprises the second plate upon which the heat source is located.
Thus, the present invention provides a light-weight, self-contained, heat-generating, food warming oven which is inexpensive to manufacture, easy to assemble, and simple to use.